Justine Joy E. Gonzaga, Gem Laurie M. Palabrica, Jeanette P. Supeda (March 2007)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Green leafhoppers are a major pest of rice, an important crop. Thus, there is a need to control them.
This study aimed to determine the insecticidal effects of methanolic extracts of C cinereus at various concentrations (100%, 75%, and 50%) against green leafhoppers (Nephotettix spp.) in terms of percent mortality ten and twenty minutes after spraying.
Green leafhoppers were obtained from rice fields and bred. Coprinus cinereus were collected from Maasin, Iloilo. Methanolic extracts were prepared and were evaporated using a rotary evaporator. One set-up with 10 leafhopper nymphs was sprayed with one concentration. A control set-up was sprayed with distilled water. The set-ups were replicated three times. Abbott’s formula was used for the computation of percent mortality at every time interval.
ANOVA results showed that a significant difference (p=.001, a= 0.05) exists in the mean percent mortality of the green leafhoppers treated with various concentrations of the methanolic extracts of C. cinereus 20 minutes after spraying. However, no significant difference exists among the means for the first ten minute interval.
The results of Fisher’s LSD Post-Hoc Test showed that green leafhoppers treated with 100% (100.0000 ± 0.0000) concentration of extract had the highest mean percent mortality 20 minutes after spraying followed by 75% (83.3333 ±5.7735) while 50% (73.3333 ±5.7735) had the lowest mean percent mortality.
This study showed that methanolic extracts of C. cinereus possess insecticidal effects against green leafhoppers.